package com.yu.tabo1688;

import java.io.UnsupportedEncodingException;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * String工具类，包含base64编解码以及16进制转换算法，主要用于计算签名
 */
public final class StringUtil {

	public static final String CHARSET_NAME_UTF8 = "UTF-8";
	public static final char[] digital = "0123456789ABCDEF".toCharArray();
	public static final String DEFAULT_DATA_TIME_FORMAT = "yyyy-MM-dd'T'HH:mm:ss.SSSZ";

	public static String format(Date date) {
		SimpleDateFormat format = new SimpleDateFormat(DEFAULT_DATA_TIME_FORMAT);
		return format.format(date);
	}

	public static String encodeHexStr(final byte[] bytes) {
		if (bytes == null) {
			return null;
		}
		char[] result = new char[bytes.length * 2];
		for (int i = 0; i < bytes.length; i++) {
			result[i * 2] = digital[(bytes[i] & 0xf0) >> 4];
			result[i * 2 + 1] = digital[bytes[i] & 0x0f];
		}
		return new String(result);
	}

	public static byte[] decodeHexStr(final String str) {
		if (str == null) {
			return null;
		}
		char[] charArray = str.toCharArray();
		if (charArray.length % 2 != 0) {
			throw new RuntimeException("hex str length must can mod 2, str:" + str);
		}
		byte[] bytes = new byte[charArray.length / 2];
		for (int i = 0; i < charArray.length; i++) {
			char c = charArray[i];
			int b;
			if (c >= '0' && c <= '9') {
				b = (c - '0') << 4;
			} else if (c >= 'A' && c <= 'F') {
				b = (c - 'A' + 10) << 4;
			} else {
				throw new RuntimeException("unsport hex str:" + str);
			}
			c = charArray[++i];
			if (c >= '0' && c <= '9') {
				b |= c - '0';
			} else if (c >= 'A' && c <= 'F') {
				b |= c - 'A' + 10;
			} else {
				throw new RuntimeException("unsport hex str:" + str);
			}
			bytes[i / 2] = (byte) b;
		}
		return bytes;
	}

	public static String toString(final byte[] bytes) {
		if (bytes == null) {
			return null;
		}
		try {
			return new String(bytes, CHARSET_NAME_UTF8);
		} catch (final UnsupportedEncodingException e) {
			throw new RuntimeException(e.getMessage(), e);
		}
	}

	public static String toString(final byte[] bytes, String charset) {
		if (bytes == null) {
			return null;
		}
		try {
			return new String(bytes, charset);
		} catch (final UnsupportedEncodingException e) {
			throw new RuntimeException(e.getMessage(), e);
		}
	}

	public static byte[] toBytes(final String str) {
		if (str == null) {
			return null;
		}
		try {
			return str.getBytes(CHARSET_NAME_UTF8);
		} catch (final UnsupportedEncodingException e) {
			throw new RuntimeException(e.getMessage(), e);
		}
	}

	private StringUtil() {
	}
}
